With advancement of the wireless broadband networks and mobile communication technologies, users have now been accustomed to use of various mobile devices to deal with their works, social communications, entertainments and so on. For conventional wireless communication systems, data and control signals necessary for wireless communication between mobile devices (or called “user equipments (UEs)”) must be processed by a base station and a backhaul core network. However, this kind of communication leads to such problems as congestion of the core network and contention for resources among devices.
To solve the aforesaid problems, another kind of wireless communication mechanism may be adopted among the UEs, i.e., the device-to-device (D2D) communication. In a broad sense, the D2D communication generally refers to that a UE can communicate with a target device directly and both can transmit and receive data with each other directly without the need of a base station. As compared to the conventional communication mechanism where UEs must communicate via a base station, the D2D communication has the advantages of reducing the transmission power, reducing the transmission delay, improving the spatial reuse efficiency and so on.
Conventional D2D communications are achieved by means of Bluetooth, Wireless Fidelity (Wi-Fi), infrared rays, or the like technologies, but these technologies are independent of the base station. Unlike the conventional D2D communication technologies, a new kind of D2D communication is implemented in a communication environment having a base station. For example, in the Long Term Evolution/Long Term Evolution-Advanced specified in the 3rd Generation Partnership Project (3GPP), a D2D communication scheme implemented in a communication environment having a base station is being planned. In this plan, the UE can search for neighbor devices rapidly within a wide range by using legally authorized frequency spectrums, and can perform D2D communications under the control and assistance of various base stations.
As described above, the new D2D communication scheme is implemented in a communication environment having a base station, so it must share wireless communication resources with the existing wireless communication systems. Therefore, how to select D2D communication resources suitable for current states of UEs is very important for the UEs. As an example, if there is lack of an appropriate resource selection mechanism, then it is likely that a UE that is to perform a D2D communication would use a same wireless communication resource as another UE within the coverage of a same base station, and this would cause interferences between respective communications of the UEs. As another example, if there is lack of an appropriate resource selection mechanism, then when a UE that is to perform a D2D communication enters into the coverage of a base station, there may be no wireless communication resource available for the UE. As a further example, if there is lack of an appropriate selection mechanism, then when a UE that is to perform a D2D communication leaves the coverage of a base station, there may be no wireless communication resource available for the UE. Because development of the new D2D communication scheme is still at an initial stage, currently there is still no effective solution to the aforesaid problems.
Accordingly, an urgent need exists in the art to provide an effective resource selection mechanism for the new D2D communication scheme.